Vehicle-tire



E. G. HULSE.

VEHICLE TIRE.

APPLICATION FILED 050.29, I920.

Patented July 19, 1921.

\ rid/max UNITED" STATES PATENT OFFICE.

EDISON G. EULSE, OF CUMBERLAND, MARYLAND, ASSIGNOR-TO KELLY-SPRINGFIELD TIRE COMPANY, OF CUMBERLAND, MARYLAND, A CORPORATION OF NEW JERSEY.

V'EHICLE-TIBE.-

Specification of Letters Patent.

Patented July 19, 1921.

Application filed December 29, 1920. Serial No. 488,910.

To all whom it may concern:

Be it known that LEmsoN G. Idursn, a citizen of the United States, resrdmg at Cumberland, in the county of Allegany and State of Maryland, have invented certain new and. useful Improvements in Vehicle- Tires, of which the following is a specification.

My invention relates to improvements in the tread portion of resilient tires, having special reference to those of the pneumat c type, but a'pplicable also to those of the solid class.

Among the principal objects of my invention attention is invlted to the following:

To provide a tread strip of the max 1mum breadth consistent with the preservation of the desired structural balance of the unitary carcass of which the tread is an integral member; to provide in the tread design such transverse contour as will function under load to deflect and effect a uniformly borne stress throughout the breadth ofthe tread, thereby also to more efliciently distribute the load into the sub-structure of the carcass, and as a further incident thereof to improve the wearing quality of such a structure over that attainable by the conventional type of tire having a tread portion designed wlth excessive curvature 1n cross sectlon and absorbing the road contact stresses and friction over a relatively small area.

Another object is to provide in the tread portion properties and characteristics conducive to a high tractive efiiclency 1n direct driving, in combination with geometrical characteristics of the tread oonfiguratlon adapted to afford the maximum protection against lateral skidding; and to so incorporate the. said desirable features in the specific design of the traction elements that the structure, as a whole, will be free of the destructive consequences of overheating, as

'well' as of inherent tendencies to disintegrate and separate under the well known effects of excessive traction wave (bem the violent stress set up by the undulation 0 that portion of the tread immediately 1n advance of the rolling contact, andespecially severe in a tread having peri heral continuity of a considerable cross sectlonal area). Also to provide a fast tread, by maintaining a continuous mid-rib, it being noted that there is a considerable loss in power involved in' driving a tire having upstandmg pro ections and without adequate provision for contlnu ty of rolling surface, the action bemg slmilar to drlving over a slightly transversely rutted road.

To the attainment of these and other use.- ful objects herein appearing this invention consists in the new and useful combination of features more fully-hereinafter defined, illustrated in the drawings and specifically olaimed.

In the accompanying drawing Figure 1 is a fragmentary section, in perspective, of a portion of a tire illustrating in part the features claimed. Fig. 2 is a partlal cross sectlonal vlew'through the plane IIII of Fig.

1 particularly illustrating the relatively fiat and wide tread portion and the characteristic features of the preferred mode of dividing the tread surface into a plurality of traction pads. Fig. 3 is a fragmentary section of the structure through the plane III-111 of Fig. 1 looking away from the center of the tire and partlcularly showing the deflection of the deep walled pad-like portions of the tread under'the tractive thrust of the tire of a driven wheel'when assumed to be rotated in the direction of the arrow A.

Throughout the several figures comprising the' drawing similar numerals of reference are employed to denote corresponding parts. Numeral 1 is the tire structure proper, which by way of illustration has been indicated as of the pneumatic type. 2 is a central rib continuous of the periphery. 3 is the preferred type of configuration employed in forming the high-standing figures comprising a portion of the tread strip, the particular function of which is hereinafter more fully set forth. It will be noted that the configuration illustrated as an especially ef ficient and preferred form has been delineated inthe semblance of a cross having asurface curvature peripherally of the tire corresponding with the normal outer circumference thereof, and having in a transverse dimotion a slightly arched surface; the arms of the cruciform figures are shown as disposed at a preferred angle of 45 degrees to the median plane of the tire structure, the side walls thereof being approximately erpendicular to the normal surface; the ual arrangement of traction pads on eitherside of the mid-rib presents a staggered arrangement. 4 is a thin, solid web, known as an air-bleeder, vertically disposed and connecting the continuous center rib with thenearest point of a proach thereto of a portion of the inner wa of an independenttraction pad.

. is the inner end of the wall of the traction pad at its shallowest point while 6 is the deepest point of one 0 said walls, particularly illustrating the construction and proortions of the traction pad design as reated to-the normal'surface curvature of the carcass 1. 7 is the'assumed line of the road bed (see Fig. 3). 8 is the assumed and exaggerated outer. circumference of' the tire structure showing the action of the traction pads at the point of road contact.

It is particularly to be noted that the design of this tire insures a high degree of tractive effort in that the traction ads have 1 been made unusually high. In see 'ng traction on smooth, wet, or otherwise difficult .road surfaces, this tread will function as illustrated in Fig. 3 of the drawing; that is, the independent elements, being relatively resilient and deflectableunder tangentially imparted road stresses, will tend to bend and momentarily clutch the road bed, setting up thereby a propulsive force to the vehicle to the power driven wheel of which the tread is attached. As several such tread elements on either side of the mid-rib 'of the tire are partially, or completely in contact with the road simultaneously it will be appreciated that the aggregate propulsive effect of them will be considerable irrespec-- tive of the tractive assistance of the continuously contacting segment of the midrib of the tread.

The eculiarly high de ree of resiliency found in my. traction pa s minimlzes the wear by abrasion due to their ability to cling to the road without slippage until the wheel has rolled a degree permitting them to lose contact by an abrupt rebound-a shallow and relatively stiff pad tends to slip and grind away, rapldly under slmilar conditions. In sharp turning, and where a wheel is sli htly out of alinement and tend ing to wabifle, the above mentioned characteristics are particularly asserted and of obvious advantage.

In drivin on roads capable of being im-.

pressed by t e tread, great clutching power is asserted by the flaring V-shaped configuration of the angularly disposed arms of the especially effective to prevent skidding, in that there are interposed transversely to the pattern. 1

The angularly disposed cross arms are path of oblique motion a pluralit of these cleat-like members effective simu taneously on both sides of the mid-rib, and offerin in conjunction with the very considerab e effort of the sharply defined edges of that member, an arrangement of surfaces, of unusual eifect against side slip;

In addition to the above enumerated adof' the load'bein uniformly borne by the resilient counterpart raised and spaced-apart Wit regard to the special advantage invherent in providing a relatively wide tread portion having a slight cross sectional cur 'vature (see Fig. 2), it is noted that the purpose of the aforesaid curvature is to insure entire breadth o the tread strip when the arch-like carcass structure is deflected under road contact, wherein the reatest deflection will occur at the center 0 the arch, assuming its supporting abutments to be the side walls of the tire carcass. As deflection occurs the convex surface of the loaded tread will flatten until the entire structure at the point of load is in a state of equilibrium, the balance of load and support being attained by the internal air pressure common to the utilization of such a tire carcass which has been shown as merely illustrative of the application of my improvements. When a tire is inflated to the proper pressure a uniform unit stress will obtain throughout the entire breadth of the tread portion at the point of load and the shocks incident to use of tires will thus be distributed over a considerable portion of the sub-structure of the carcass, tending to mitigate the danger of ru turing the structure.

mm the foregoing it will be appreciated that my invention provides a tire tread. portion, combining, in a unitary and economically molded structure, a combination of properties and features not heretofore attained in any other like tread. 4

Having thus described m invention, what I claim as new therein an desire to secure by Letters Patent is:

1. A tire tread of resilient material, comprising a substantially fiat surface in cross section, a continuous annular mid-rib, and

traction pads on each side of said rib, said pads, in plan view, forming cruciform pat-1 terns adapted to remain continuously in contact with the road surface throughout their period of traction and to yieldingly clutch the road bed momentarily under the tangentially imparted traction stresses.

2. A tire tread of resilient material, comprising a substantially flat surface in cross section, a continuous annular mid-rib, and counter art raised and spaced-apart traction a s on each side of said rib, said pads, in an view, forming cruciformpatterns, the readth of the cross arms being less than the depth thereof, and less than the breadth 126 I lnentari y under traction stresses. 130

3. A structure of the class described comprising, in cross section, a slightly arched tread portion adapted to assume a flattened contour under load, thereby apportioning and equalizing the bearing stresses transmitted into the sub-structure throughout its breadth, a continuous annular mid rib, and counterpart resilient raised traction pads on each side thereof, in plan view constituting cruciform patterns, said pads being in spaced and staggered relation and disposed, as of the obliquity of their arms to the midrib, at approximately forty-five (45) degrees, whereby in driving ahead or reversing a plurality of V-shaped projections will yieldingly clutch the road, and whereby in oblique skidding there are interposed transversely of the direction of motion a plurality of resilient cleat-like projections.

4. A resilient tire, having a tread portion substantially flat in transverse section and adapted to deflect under load to conform with the road, whereby stresses are apportioned and equalized in the sub-structure; a continuous high-standing and relatively flat mid-rib in said tread adapted to partially relieve the load from the traction pads, whereby retardation to rolling is reduced; independent high-standing traction pads on each side of the mid-rib, of cruciform pattern and staggered with respect to complementary opposed pads, and having their arms angularly disposed with respect to the median plane of the tire, the surfaces of said pads lying in the plane of the road when under load whereby a plurality of them are simultaneously in yielding contact therewith, said pads having deep and substantially vertical side walls and relatively narrow cross arms, in plan view, and constructed of highly resilient material, whereby each pad is adapted to freely bend in all directions and to twist with respect to its contacting surface, thereby momentarily clinging to the road while bending without slippage, whereby traction is sustained and abrasion of the material due to slippage minimized, said pads presenting a V-shaped clutch in the direction of the circumference of the tire and obliquely disposed cleat-like projections to the direction of side slippage whereby a skidding tendency is corrected.

In testimony whereof I afiix my signature.

EDISON G. HULSE. 

